1. Field of the Invention
The present invention relates to a liquid discharge head for recording by discharging liquid as flying droplets which adhere to a recording medium, and a method of manufacture therefor. The invention also relates to a liquid discharge recording apparatus.
The present invention relates to a liquid discharge head, a method of manufacture therefor, and a liquid discharge apparatus applicable to a printer that records on a recording medium, such as papers, threads, textiles, cloths, leathers, metals, plastics, glass, wood, ceramics, and also, applicable to a copying machine, a facsimile equipment provided with communication system, and a word processor provided with the printing unit, among some others. Further, the invention also relates to those applicable to recording systems for industrial use which are structured by the complex combination of various kinds of processing apparatuses. Here, the term xe2x80x9crecordingxe2x80x9d referred to in the specification hereof means not only the provision of meaningful images, such as characters, graphics, but also, it means the provision of such meaningless images as patterns recorded on a recording medium.
2. Related Background Art
Conventionally, there has been known an ink jet recording apparatus that records by discharging ink serving as recording liquid form the orifices formed for the liquid discharge head as an excellent recording apparatus in that it is capable of recording at high speeds in a lesser amount of noises. Along with the advances of printing technologies in recent years, the ink jet recording apparatus is required to be able to record in higher speeds in higher precision. As a result, the size of the discharge ports (the orifice diameter) becomes finer, and at the same time, the discharge ports are formed in higher density.
FIG. 1A is a perspective view which schematically shows one example of the liquid discharge head used of the conventional ink jet recording apparatus. FIG. 1B is a cross-sectional view thereof, taken in the flow path direction.
As shown in FIGS. 1A and 1B, the head comprises an orifice plate 102 having a plurality of orifices 101 for discharging ink, and the head unit 110 which is bonded to the orifice plate 102 by use of bonding agent 106 in order to supply ink to be discharged from the orifices 101. The head unit 110 is provided with the flow paths 112 communicated with the orifices 101 to supply ink to be discharged from the orifices 101; the ceiling plate 111 which forms the flow paths 112; and the energy generating elements 114 that generate energy for discharging from the orifices 101 the which ink supplied from the flow paths 112. Then, the unit comprises the substrate 113 that forms the flow paths 112 together with the ceiling plate 111.
Here, for the orifice plate 102, fine orifices 101 are arranged in order to discharge ink. Since the orifices 101 present an important factor of which the discharge performance of the liquid discharge head is dependent, it is required for the orifices to provide an excellent machinability, and resistance to ink, because the orifices are directly in contact with ink.
Conventionally, as the material of the orifice plate that satisfies such an operational condition as described above, there is a metallic plate, such as SUS, NI, Cr, Al or a resin film material, such as polyimide, polysulfone, polyethersulfone, polyphenylene sulfide, polypropylene, polyether etherketon, among some others. If a metallic plate is used for the orifice plate, it is generally practiced to use a method, such as electrocasting, for the formation of the orifices. If a resin film is used for the material of the orifice plate, it is generally practiced to use a method for forming the orifices by processing the resin film finely by means of the excimer laser ablation.
However, when the orifice plate is bonded to the head main body, it is extremely difficult to connect the fine discharge ports with the flow paths without any gaps, which should be communicated with the discharge ports. Particularly when the orifice plate formed by the resin film should be bonded to the head main body, the orifice plate may often be fixed in a deflected condition due to the flexibility of the orifice plate. in this case, the direction of the plural discharge ports formed for the orifice plate is allowed to be varied eventually. The products thus manufactures should be refused. Also, if the water repellent layer should be provided for the surface of the filmed resin, there is a fear that the water repellent layer is subjected to damages when the resin is handled. As a result, an utmost care should be exercised for handling when the bonding operation is carried out for the orifice plate.
Further, for the color image formation which has rapidly been in more demand, particularly for the formation of photographic color images, it is required to place the ultrafine ink droplets exactly in higher density on the desired positions on a recording medium. Therefore, it is extremely important to maintain the exact positional relationship between the four-color head units, yellow, cyan, magenta, and black, for example.
FIG. 2 is a perspective view which schematically shows one structural example of the liquid discharge head used for the conventional ink jet recording apparatus which is capable of forming color images. As shown in FIG. 2, the conventional ink jet recording apparatus capable of forming color images is provided with the liquid discharge head having the orifice plates 202a to 202d and the head units 210a to 210d for each of the plural colors. Then, the head units 210a to 210d are arranged on the predetermined positions of the frame 230, respectively.
Here, as a technique to enhance the positional precision between the head units 210a to 210d with each other, a method or the like is adopted to connect and bond the head units 210a to 210d with the frame 230 corresponding to each color in such a manner that each position of discharge ports of the head units 210a to 210d for the respective colors is recognized in advance by the application of image processing, and then, each position of the discharge ports thus recognized is offset from the positioning standard set on the frame 230 for the printer main body.
Now, hereunder, the description will be made of the method for manufacturing the liquid discharge head described above. At first, the flow path walls and the electrothermal transducing elements serving as discharge energy generating elements are arranged on the silicon substrate. Then, the ceiling plate formed also by a silicon substrate, for example, is bonded with this substrate. After that, by use of the diamond blade for adjusting the positions of the flow paths and the like, the head units are cut per color. Then, each of the orifice plates is bonded to the head unit thus cut by use of a bonding agent, such as epoxy resin.
Subsequently, the position of the head unit bonded to the orifice plate is recognized by means of the image processing, thus connecting and bonding it with the frame after adding the offset value with respect to the positioning standard set in advance for the frame. In this manner, the positioning relationship between four head units is determined relatively.
However, with respect to a liquid discharge head manufactured by the conventional method of manufacture as described above, there is a problem which may make it difficult to maintain the placement accuracy for the ink jet recording apparatus which should be provided with a resolution of as high as 1200 dpi to 1440 dpi or even as high as 2400 dpi as to the relative relationship between the head units for each color in recent years. If, for example, the liquid discharge head of four-color structure should be manufactured, there is a need for controlling six axes, that is, X, Y, Z, xcex8x, xcex8y, and xcexcz, for the relative positions between the head units for each color as shown in FIG. 1A.
In accordance with the conventional method of manufacture, however, the positioning is carried out on the basis of the discharge ports as having been observed. Therefore, although the X, Y, and xcex8z axes can be aligned in high precision, the positioning accuracy of the remaining axes, Z, xcex8x, and xcex8y, becomes dependent of the adjustment precision of the jig used for the assembling device eventually. Particularly for the xcex8y axis, a greater placement deviation may take place on a recording medium if any minute deviation occurs due to the adjustment accuracy of the jig for the assembling device.
Also, as to the Z axis, minute deviations are allowed to occur between each of the head units. As a result, difference may take place in the advancing amount of the rubber blade that wipes stains and overly viscose ink on the orifice plate or in the capping which is needed for preventing ink from being dried, thus creating gaps eventually. Further, each of the head units is clamped to be set on the frame individually. As shown in FIG. 2, therefore, there is a need for securing a gap between each of the head units so that the jig clamp can be placed between them, and a problem is encountered that the four-color integrated liquid discharge head is made greater inevitably.
It is an object of the present invention to provide a liquid discharge head presenting an excellent operativity without any fear that the head performance is degraded when the orifice plate having discharge ports formed therefor is bonded to a head main body having flow paths provided therefor, as well as to provide a method of manufacture therefor, and a liquid discharge apparatus.
It is another object of the invention to provide a liquid discharge head capable of setting the relative positions between discharge ports for plural colors in high precision, at the same time, being capable of enhancing the precision of wiping and capping thereof, as well as to provide the method of manufacture therefor, and a liquid discharge apparatus.
It is still another object of the invention to provide a liquid discharge head capable of implementing the miniaturization thereof in higher quality at lower costs, and also, the enhancement of productivity and reliability, as well as to provide the method of manufacture therefor, and a liquid discharge apparatus.
It is a further object of the invention to provide a liquid discharge head having good discharge efficiency with the extrusions that enter the flow paths from the orifice plate, which can be easily manufactured by a simple manufacturing apparatus in a shorter period of time, as well as to provide the method of manufacture therefor, and a liquid discharge apparatus.
It is still a further object of the invention to provide a liquid discharge head capable of recording high quality images even for the arrangement of discharge ports which should be further in progress so as to require a higher density thereof, as well as to provide the method of manufacture therefor, and a liquid discharge apparatus.
It is still another object of the invention to provided a method for manufacturing a liquid discharge head which comprises the steps of providing a head main body having liquid flow paths, and an aperture surface having flow path openings communicated with the flow paths; providing a discharge port plate having extrusions each on the circumference of an inside opening communicated with each of the discharge ports, being on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid, and a base having a joint surface in contact with said discharge port, the discharge port plate being arranged in a state of said discharge port surface and said joint surface formed integrally to be in contact; bonding the aperture surface and the inner face to fit the extrusions into the flow path openings by pressing the head main body and the base in the direction of the head main body and the base approaching each other with the discharge port plate between them; and separating the base from other members.
It is still another object of the invention to provide a method for manufacturing a liquid discharge head comprising the steps of providing a member for structuring a head main body having grooves becoming liquid flow paths, and an aperture surface having edge openings of the grooves; providing a discharge port plate having extrusions each on the circumference of an inside opening communicated with each of the discharge ports, being on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid; bonding the aperture surface and the inner face to fit the extrusions into the edge openings by enabling the member for structuring the head main body and the discharge pot plate to approach each other; and forming the liquid flow paths by bonding the member for structuring the head main body with a plate member for closing the grooves.
It is still another object of the invention to provide a method for manufacturing a liquid discharge head comprising the steps of providing a member for structuring a head main body having grooves becoming liquid flow paths, and an aperture surface having edge openings of the grooves; providing a discharge port plate having inside openings each communicated with each of the discharge ports, being on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid; bonding the aperture surface and the inner face to communicate the discharge ports with the edge openings by enabling the member for structuring the head main body and the discharge pot plate to approach each other; and forming the liquid flow paths by bonding the member for structuring the head main body with a plate member for closing the grooves.
It is still another object of the invention to provide a method for manufacturing a liquid discharge head comprising the steps of providing a member for structuring a head main body having grooves becoming liquid flow paths, and an aperture surface having edge openings of the grooves; providing a discharge port plate having recessed portions on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid; bonding the aperture surface and the inner face to communicate the discharge ports with the edge openings by enabling the member for structuring the head main body and the discharge pot plate to approach each other; and forming the liquid flow paths by bonding the member for structuring the head main body with the plate member by enabling the plate member for closing the grooves to abut against the inner face of the recessed portions.
It is still another object of the invention to provide a method for manufacturing a liquid discharge head comprising the steps of providing a member for structuring a head main body having grooves becoming liquid flow paths, and an aperture surface having edge openings of the grooves; providing a discharge port plate having extrusions each on the circumference of an inside opening communicated with each of the discharge ports, being on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid, and a base having a joint surface in contact with said discharge port surface in an integrated state of the discharge port surface and the joint surface being in contact; bonding the aperture surface and the inner face to fit the extrusions into the edge openings by pressing the member for structuring a head main body and the base in the direction of the member for structuring a head main body and the base to approach each other with the discharge plate between them; forming the liquid flow paths by bonding the member for structuring the head main body with a plate member for closing the grooves; and separating the base from other members.
It is still another object of the invention to provide a liquid discharge head which comprises a plurality of head main bodies having liquid flow paths, and an aperture surface provided with flow path openings communicated with the flow paths; a discharge port plate having extrusions each arranged on the circumference of inner openings communicated with the discharge ports, being on the inner face on the side opposite to the discharge port surface having discharge ports for discharging liquid, the plurality of head main bodies being arranged and bonded to the discharge port plate shared by them, and each of the aperture surface and inner faces of the plurality of head main bodies being bonded to fit the extrusions into the flow path openings.
It is still another object of the invention to provide a liquid discharge head which comprises a head main body having liquid flow paths, and an aperture surface provided with flow path openings communicated with the flow paths; a discharge port plate having extrusions each arranged on the circumference of inner openings communicated with the discharge ports, and grooves arranged on the circumference of the extrusions, being on the inner face on the opposite to the discharge port surface provided with discharge ports for discharging liquid. For this liquid discharge head, the aperture surface and the inner face are bonded to fit the extrusions into the flow path openings.
It is still another object of the invention to provide a liquid discharge head which comprises a member for structuring a head main body having an aperture surface provided with grooves becoming liquid flow paths, and an aperture surface provided with the edge openings of the grooves; a plate member for covering the grooves by being bonded to the member for structuring a head main body; a discharge port plate having recessed portions arranged on the inner face on the side opposite to the discharge port surface provided with discharge ports for discharging liquid. For this liquid discharge head, the aperture surface and the inner face are bonded to communicate the discharge ports with the edge openings, and the plate member is allowed to enter the recessed portions to be bonded with the member for structuring a head main body for the formation of the flow paths.
It is still another object of the invention to provide a method for manufacturing a discharge port plate used for a liquid discharge head comprising the steps of forming on an elongated resin film the recessed portions for the formation of a plurality of discharge ports; arranging a laminate layer on the surface of the resin film having no recessed portions for the formation of the plurality of discharge ports; forming discharge ports for the recessed portions on the resin film for the formation of the plurality of discharge ports; bonding the resin film to the head main body; and removing the laminate layer.
In accordance with the present invention, the laminate layer is laminated on the surface of the orifice plate. Therefore, the surface of the orifice plate follows the flat plane of the laminate layer, hence making it possible to bond the orifice plate with the head main body in an excellent flatness. With the bonding method which provides the extrusions for the orifice plate in the positions of the flow path apertures of the head main body, in particular, it becomes possible for the extrusions on the orifice plate side to enter the flow paths on the head main body side. Then, when being bonded, there is no possibility that the extrusions and the discharge ports are deformed or damaged. Also, the water repellent layer on the surface of the orifice plate is protected by the laminate layer, thus eliminating a fear that the water repellent layer is damaged.
Also, the thickness of the laminate layer is made sufficiently larger than that of the orifice plate film when the laminate layer is formed with resin film. The robustness of the laminate layer becomes greater. As a result, when being bonded, the surface of the orifice plate can follow the laminate layer to maintain the flatness of the orifice plate in good condition. Also, if the laminate layer is formed by stainless steel, this layer can acquire robustness greater than the resin. Therefore, at the time of being bonded under pressure, the face plane of the orifice plate can be maintained flatly in a better condition.
For one orifice plate, a plurality of discharge port arrays are arranged at a time or sequentially corresponding to a plurality of flow paths arranged for a plurality of head units, respectively. Then, on the discharge port side of the orifice plate, a robust jig is arranged to hold the orifice plate horizontally. The head unit clamped by the jig which has been adjustably set vertically to the surface of the jig that holds the orifice plate is bonded to the surface of the head unit where the orifice plate is bonded. Lastly, with the orifice plate serving as reference, each adjustment axis of the head unit is made to follow it, hence determining the relative positions between a plurality of head units. As a result, it becomes possible to implement the manufacture of a highly precise color liquid discharge head without a higher production technologies and techniques.
Further, in accordance with the present invention, the discharge efficiency of liquid is enhanced, because of the presence of the extrusions that enter the flow paths, and at the same time, the working efficiency becomes excellent, because the extrusions are formed together with the discharge ports simultaneously. Particularly, with the formation of the extrusion and discharge ports by the irradiation of laser beams, the operation becomes simpler. In this case, the laser beams are irradiated with the mask, while changing the transmissivities thereof locally. Then, the formation is made in good precision. Here, therefore, in accordance with the present invention, it becomes possible to shorten the time required for processing to manufacture a liquid discharge head having an excellent discharge efficiency, hence implementing the enhancement of the productivity thereof.
Also, there is no need for any positioning that may be performed excessively when executing each process. The manufacture becomes easier, while it becomes possible to simplify the manufacturing apparatus.
Also, with the grooves formed on the circumference of the extrusions, it becomes possible to prevent the bonding agent used for bonding the orifice plate from flowing into the flow paths and discharge ports as well. Here, it enhances the operational efficiency if these grooves are also formed with extrusions and discharge ports at a time.
In addition, if it is arranged to bond the orifice plate and the substrate or the ceiling plate at first, and then, to bond the ceiling plate or the substrate to this bonded body, the bonded edges of the substrate and the ceiling plate is aligned with the orifice plate surface. Therefore, the manufacture of the head becomes simpler and more efficient. Particularly, if a cut-out portion is arranged for the orifice plate to receive at least a part of the ceiling plate or the substrate or if the extrusions are arranged for a part of the orifice plate to enter the flow path, it becomes possible to manufacture the head simpler in precision higher still.
Also, the end portion of each flow path is cut without requiring any grinding. Then, there is no possibility that the nozzle walls are chipped off or broken in the vicinity of each discharge port even if the nozzle pitches become highly densified. As a result, it is possible to discharge desired recording droplets in good condition.